Improved Circularity Metrology of Small Cylindrical Workpieces by the Segmenting-stitching Technique

Abstract

To address the alignment and measuring force problem in the segmenting-stitching technique for the circularity metrology of small cylindrical workpieces (diameter less than 1.5 mm and length less than 10 mm), a magnet combination jig method is proposed. A small round magnet is attached between the round magnetic jig and small cylinder, and the other end of the small cylindrical workpiece is attached to some cylindrical magnets. Thus, the smaller cylinder can be put in the V-groove and measured successfully with the magnet combination. For ver-ifying the advantage of the magnet combination jig, four measurement quality evaluations are proposed: the circumferential deviation of neighbor arc contours, radial deviation of neighbor arc contours, angle of inclina-tion between the V-groove and small cylinder, and curvature of the obtained arc. The results show that the matching coefficient is enhanced by 98%, the Euclidean distance of overlap parts of neighbor arc contours is reduced by 68%, the position error is reduced 27%, and the average curvature of the arc contours is improved. It can be concluded that the measuring quality can be enhanced prominently by this magnet combination method for the segmenting-stitching method.